Gout

Comments:
High power view of gouty tophi which are large aggregates of monosodium urate crystals surrounded by an intense inflammatory reaction consisting of foreign body giant cells, histiocytes, and lymphocytes. Locations where gouty tophi can be seen include the joints, ligaments, tendons, peri-articular soft tissues, bursae, and less frequently in earlobes, nasal cartilages, kidneys, and skin of fingertips. Monosodium urate crystals are best visualized in alcohol-fixed tissues as long, needle-shaped negatively birefringent crystals.